Energy-consuming devices, such as electric appliances, need to be supplied with electric current as a function of their use, energy efficiency or operational cycles. On the one hand, the demand for electrical energy of a single device is not continuous. For example, the energy demand of an electric car depends on the planned use and charge state. On the other hand, distributed electric power plants, in particular power supply units based on renewable energies, cannot continuously provide power. Rather, the energy generation depends on external factors, such as solar irradiation or deployable wind power. Therefore, an efficient management of the fluctuations of the power supply and the fluctuations in the demand in the respective power grid is desirable. This issue becomes more and more imminent when renewable energy resources are integrated into the power systems.
Generally, a cost function can be defined that takes into account the availability of distributed energy resources and the consumption profiles of, e.g., electric devices to be supplied with energy. In order to obtain the most efficient use of energy consumers, energy generators and storage capabilities, such global cost functions need to be optimized resulting in suitable profiles for the operation of the devices included in such complex energy distribution systems. The computational efforts for optimizing cost functions scale with the number of devices included in the smart grid network. The computational and communicational resources required for minimizing the cost functions increase in complexity when additional properties for the devices involved are taken into account. For example, modern devices may act as electric energy source, energy storage and/or energy sink, i.e. an electric consumer.